Stock material or miscellaneous articles – Structurally defined web or sheet – Physical dimension specified
Reexamination Certificate
1999-03-03
2001-08-28
Acquah, Samuel A. (Department: 1711)
Stock material or miscellaneous articles
Structurally defined web or sheet
Physical dimension specified
C524S492000, C524S494000, C524S423000, C524S437000, C524S425000, C524S493000, C428S331000, C428S328000, C428S330000, C428S343000
Reexamination Certificate
active
06280835
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a novel thermoplastic acrylic resin brittle film, and more particularly, to a thermoplastic acrylic resin brittle film which has excellent transparency and weatherability, can be formed into a thin film, is brittle and easily torn, and is advantageously used for labels and stickers, such as certificate stamps and sealing labels, and display stickers, such as marks for danger prevention and marks for commercial products, and also for prevention of forgery of passports.
Further, the present invention relates to a novel thermoplastic acrylic resin brittle film for laser marking. Additionally, the present invention relates to an adhesive sheet using the thermoplastic acrylic resin brittle film.
PRIOR ART OF THE INVENTION
Brittle films have heretofore been used as base films for labels which must be prevented from transfer, such as labels for theft prevention and labels of certificate stamps, by taking advantage of the property of the films, i.e., brittle and easily torn.
As the brittle film used for the above applications, various films, such as (1) a brittle film for marking which has a thickness of about 30 to 60 &mgr;m and comprises a resin composition containing 100 parts by weight of a vinyl chloride resin, about 5 to 20 parts by weight of an alkyl methacrylate resin, 5 to 30 parts by weight of a plasticizer, and pigments (Japanese Patent Publication No. Showa 54(1979)-34420), (2) a substantially transparent sheet having a layer composed of glass microspheres having a refractive index of 1.8 or more alone (Japanese Patent Application Laid-Open No. Showa 50(1975)-129195), and (3) a safety label using the above transparent sheet as the film which is brittle and easily torn (Japanese Patent Publication No. Showa 61(1986)-47426), have been proposed.
However, because the above brittle film for marking (1) is colored due to pigments, this film has drawbacks in that information placed under the film cannot be observed and recognized through the film, and that the film has insufficient brittleness, poor flexibility, and inferior fitting when the film is attached to curved surfaces. Moreover, a plasticizer must be used in combination because the film comprises a vinyl chloride resin, and the use of a plasticizer causes the possibility that adhesion of an adhesive material to the film becomes insufficient due to bleeding out of the plasticizer when the film is attached to an article through the adhesive material.
The above transparent sheet (2) and the above safety label (3) using the transparent sheet have drawbacks in that the sheet and the label are inevitably expensive because expensive glass microspheres are used and that complicated procedures are required for uniformly arranging the glass microspheres into a layer composed of the glass spheres alone.
A transparent brittle film which has a total light transmittance of 30% or more and is prepared from a composition containing 100 parts by weight of a vinyl chloride resin and 80 to 250 parts by weight of a material which is incompatible with the vinyl chloride resin and has an average particle size of 10&mgr; or less and a refractive index of 1.7 or less, is also proposed (Japanese Patent Application Laid-Open No. Showa 64(1989)79237). However, because this transparent brittle film contains a vinyl chloride resin as the sole resin component, this film has a drawback in that formation of a film is difficult unless a large amount of a plasticizer, such as about 20 to 80 parts by weight of a plasticizer per 100 parts by weight of the vinyl chloride resin, is contained (35 parts by weight of a plasticizer was contained in an example), and this causes the problem that hardness and brittleness of the film are not always satisfactory. Moreover, similarly to the case of the above brittle film for marking (1), there is the possibility that adhesion of an adhesive material to the film becomes insufficient due to bleeding out of the plasticizer when the film is attached to an article through the adhesive material. Transparency and weatherability are not always sufficient because a vinyl chloride resin is used as the sole resin component. Resin compositions comprising a vinyl chloride resin have another drawback in that disposal and incineration of waste materials are difficult.
SUMMARY OF THE INVENTION
Accordingly, the present invention has an object of overcoming the drawbacks of conventional brittle films and providing a brittle film which has excellent transparency and weatherability, is brittle and easily torn, shows a suitable degree of flexibility and hardness, exhibits excellent adhesion to an adhesive material when the film is attached to a article through the adhesive material, is disposed or incinerated without problems, and can be produced inexpensively by a simple process.
As the result of the extensive studies conducted by the present inventors to develop a brittle film having the above advantageous properties, it has been found that the above object can be achieved by a film prepared from a resin composition comprising specific amounts of a thermoplastic acrylic resin having a specific elongation at break, a filler having a specific average diameter and specific diameters of constituting particles, and a plasticizer which is used optionally. The present invention has been completed on the basis of this knowledge.
Thus, the present invention provides:
(1) A thermoplastic acrylic resin brittle film prepared from a resin composition which comprises (A) 100 parts by weight of a thermoplastic acrylic resin having an elongation at break of 10 to 180%, (B) 10 to 70 parts by weight of at least one type of filler selected from the group consisting of (a) fused silica comprising aggregates of particles having an average diameter of the particles in the range of 5 to 20 &mgr;m and diameters of the particles in the range of 0.5 to 100 &mgr;m, (b) aluminum hydroxide comprising aggregates of particles having an average diameter of the particles in the range of 1 to 20 &mgr;m and diameters of the particles in the range of 0.2 to 50 &mgr;m, (c) barium sulfate comprising aggregates of particles having an average diameter of the particles in the range of 1 to 20 &mgr;m and diameters of the particles in the range of 0.2 to 50 &mgr;m, and (d) calcium carbonate comprising aggregates of particles having an average diameter of the particles in the range of 0.5 to 20 &mgr;m and diameters of the particles in the range of 0.1 to 50 &mgr;m, and (C) 0 to 30 parts by weight of a plasticizer;
(2) A thermoplastic acrylic resin brittle film described in (1), which has a tear strength of 3.0 to 20.0 g;
(3) A thermoplastic acrylic resin brittle film described in any of (1) and (2), which has a tensile strength at break of 1.0 to 3.0 kg/mm
2
and an elongation at break of 2.0 to 20.0%; and
(4) A thermoplastic acrylic resin brittle film described in any of (1) to (3), which has a thickness of 20 to 80 &mgr;m.
DETAILED DESCRIPTION OF THE INVENTION
It is necessary that the thermoplastic acrylic resin used as component (A) in the film of the present invention have an elongation at break in the range of 10 to 180%. When the elongation at break is outside this range, it is difficult that a brittle film having a desired elongation at break is obtained. The elongation at break of the thermoplastic acrylic resin is preferably in the range of 20 to 140%. For the measurement of the elongation at break, a sample is conditioned by being left standing at the temperature 22 to 25° C. for 1 hour or more. The conditioned sample having a rectangular shape of a size of 20×100 mm is subjected to the test by using an Instron-type tensile tester under the condition of an extension speed of 5 mm/minute, a chart speed of 100 mm/minute, and a distance between chucks of 50 mm. The test is repeated 6 times, and the values of the elongation are averaged to obtain the elongation at break.
The above sample is prepared by coating a polyethylene phthalate film used as the support with a solution which is obtained by mixing the therm
Acquah Samuel A.
Asahi Kagaku Kogyo Co., Ltd.
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Rajguru U. K.
LandOfFree
Thermoplastic acrylic resin brittle film does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoplastic acrylic resin brittle film, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic acrylic resin brittle film will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2531954